structure of the atom

write the molecular the molecular formula for calcium phosphate

• Ca₂po₄

• Ca₂(po₄)₂

• Ca₃(po₄)₂

• CaPO3

Answer explanation

BY CRISS CROSS METHOD

Ca po₄

_{valency Ca is 2 PO4 is 3}

_{so Ca3 (PO4)2}

Tags

NGSS.MS-PS1-1

some boron atoms have mass number 10 and some have mass number 11 these Boron atoms with different mass numbers are called

• isobars'

• isotopes

Answer explanation

dAtoms of an element having same atomic number but different mass numbers are called isotopes. Since, mass number = number of protons + number of neutrons.

velency element B have atomic number 9 determine the valency

• 1

• 2

• 3

• 4

Answer explanation

The electronic configuration of an element of atomic number 9 is 2, 7. It requires one electron to get a stable noble gas configuration. Hence its valency is 1.

mass of a Proton is times that of an electron

• 1842

• 1846

• 1837

• 1848

Answer explanation

Mass of an electron is approximately 1/1837 times that of mass of proton. .

the carbon element has three isotopes having the same atomic number of 6 but different mass numbers of 12 13 and 14. Please confirm whether this statement is true or false.

• True

• False

Answer explanation

Carbon occurs naturally in three isotopes: carbon 12, which has 6 neutrons (plus 6 protons equals 12), carbon 13, which has 7 neutrons, and carbon 14, which has 8 neutrons

name the isotope used to treat goiter

• Phosphorus

• Cobalt

• iodine

• sulphur

Answer explanation

I or Iodine-131 is a radioactive isotope used in the treatment of goiter, a disease associated with the thyroid gland

write the formula for calculating the maximum number of electrons in an Orbit

• 2n

• 2n²

• n²

• n

Answer explanation

2 n ²

Hence, the maximum number of electrons that can be accommodated in an orbit is given by the formula 2 n ² where “n” is the number of orbit.

• ISOBARS'

• ISOTOPES'

• ISOTONES'

• ISOMERS'

Answer explanation

B

SAME ATOMIC NUMBER BUT NOT SAME NEUTRONS

Tags

NGSS.MS-PS1-1

nucleus consists of

• Protons and electrons

• protons

• protons and neutrons

• electrons

Answer explanation

Atomic nuclei consist of electrically positive protons and electrically neutral neutrons

Assertion: inert gas elements show zero valency.

Reason : atoms of inert elements have filled the outermost orbit.

• A and R correct.

  R is the correct explanation of A

• A and R correct.

  R is not correct explanation of A

• A is true R is false.

• A is false and R is true

Answer explanation

These elements have a fully-filled outermost valence shell or orbit, hence inert in nature. Their valency is zero as their valence shells are .fully filled with electrons.